For example, take the first 909 featured in the thread (The Author, Level 2 Shops). If you are just looking at the images, it doesn’t make sense. I fire the Jaeger 7 Lancer “out in the open”. And I do it twice. The shot appears to ring out over the beach, into the cemetery.
Yet, the only time “Gunshot Heard” is flagged is when the guards are blindly firing their weapons from the cemetery. I walk down the stairs… and not only are the Civilian NPC’s at the beach, the port, and the apartments just going about their business. Every guard that was alerted went to the cemetery because that is the only place where shots were heard.
The biggest puzzle there was the concept of “open air”. That 909 is proof that in HITMAN, in fact in all video games, there is no such thing as “open air” to carry “sound” (which is another thing that doesn’t actually exist). You can hear a sound because a game plays a Sound file for YOU (The player) but in the video game no NPC in there can actually hear anything.
It’s a puppet show basically… the puppets move and act like they can ‘see’ and ‘hear’ and ‘talk’ but they cannot.
The belief at the time of this discovery was that the area I was in… imagine that the level as nothing more than a set of interconnected invisible “corridors/boxes” representing areas you can walk around in… The idea was that these sections - called Volumes in some engines like UE4 - require rules between them for some things that seem basic like passing on “sound” to help create the illusion of sound travelling. But in that particular spot the passing on of such value was either very limited or maybe it doesn’t work.
HITMAN doesn’t have an AI in the purest sense, only a set of decision trees and conditions. The 909 issue demonstrates that when some of them are missing, you can make the seemingly impossible happen.